On Wednesday, following a few snarky exchanges between Louis Tomlinson and Malik's friend, British music producer Naughty Boy, Malik fired back himself.
"Remember when you had a life and stopped making bitchy comments about mine?" wrote Malik, 22, in a Tweet directed at Tomlinson.
@Louis_Tomlinson remember when you had a life and stopped making bitchy comments about mine ?— zaynmalik (@zaynmalik) May 6, 2015
It all started when Naughty Boy, 30, Tweeted a photo of himself with Malik, captioned "Replace this," a seeming nod to the unsubstantiated rumor that One Direction might replace Malik following his departure from the band in March. (Malik re-Tweeted the snap.)
Fans have also pointed out that the Tweet may be a reaction to an Instagram video posted by Liam Payne, in which he jokingly suggests a new fifth member.
Replace this . pic.twitter.com/Dis0Tfd7cz— Naughty Boy (@NaughtyBoyMusic) May 6, 2015
Tomlinson, 23, seemingly in response to the photo, wrote this Tweet: "Remember when you were 12 and you used to think those Mac filters for your pictures were cool haha ! Some people still do HA!"
Naughty Boy, whose real name is Shahid Khan, retorted: "And some people can't even sing... but who's complaining when there's auto tune eh."
@Louis_Tomlinson and some people can't even sing.. but who's complaining when there's auto tune eh— Naughty Boy (@NaughtyBoyMusic) May 6, 2015
Tomlinson responded to the producer not long after: "Jesus forgot you were such an in demand producer .... How does it feel to be riding on the back of someone else's career?" It was this Tweet that prompted Malik's response to his former bandmate.
@NaughtyBoyMusic Jesus forgot you were such an in demand producer .... How does it feel to be riding on the back of someone else's career ?— Louis Tomlinson (@Louis_Tomlinson) May 6, 2015
On Thursday, Malik tried to set the record straight: "Don't know why I'm being attacked for defending myself," he Tweeted. "People got it twisted! I love my fans ?! Every single one of you x."
Don't know why I'm being attacked for defending myself , people got it twisted! I love my fans ?! Every single one of you x— zaynmalik (@zaynmalik) May 7, 2015
Not long after, Tomlinson thanked his fans for their support.
Our fans support really has been a different class ! Huge love to you guys !!— Louis Tomlinson (@Louis_Tomlinson) May 7, 2015
This isn't the first time that Naughty Boy and Tomlinson have let it fly on Twitter. Soon after Malik left, Tomlinson accused Naughty Boy of trying to "wind [One Direction] fans up." That fight ended with the producer leaking a song with Malik on vocals called "I Won't Mind." (It was removed the next day.)
While they were in the band together, Tomlinson was closest to Malik, as a source told PEOPLE back in March. Tomlinson was "the most worried" when Malik left in the middle of the band's On the Road Again world tour.
The two even have matching tattoos. Tomlinson has "Bus 1" inked on his right arm, and Malik's is on his left hand – they represent the tour bus they slept in together while on the road.
So … who's gonna be the first to say goodbye (to their Bus 1 tattoo)?